Art of surfacing one metal with another



March 30, 1937. F. G ETTELMAN 2,075,518

ART OF SURFACING ONE METAL WITH ANOTHER Filed Oct. 4, 1934 INVENTOR BY WM w M ATTORNEYS Patented Mar. 30, 1937 UNITED STATES PATENT OFFICE Fredrick Getteiman, Milwaukee, Wis.

Application October 4, 1934, Serial No. 746,881

3 Claims.

This invention relates to improvements in the art of surfacing one metal with another.

It is the primary object of the invention to provide means for producing mechanically the equivalent of a metallic plating operation. While the invention is applicable to metal sheets, it is of particular importance in the surfacing of the interiors of metal containers to produce a smooth surface metallic ply.

At present composite sheets of diflerent metals are being made by welding a thin sheet of one metal to a more substantial supporting sheet of the other. For example, a thin sheet of stainless steel has been welded toa sheet of iron or ordinary steel and the composite sheet has been rolled to attempt to eliminate irregularities produced by the welding and to attempt to unite the two sheets throughout their extent. Also, metallic surfaces have been sprayed with molten metal by means of the so-called metal gun. It has also been attempted to melt one metal and pour it on to another, as for example, the surfacing of iron with molten aluminum, but the aluminum coating is quite irregular and rough when made in this manner. Still another attempt at coating has been made through the use of an electroplatingprocess. This is satisfactory for some purposes, but none of the above methods of coating is sufficiently cheap or sufiiciently practlcable to be of general application, and none of the above methods of coating is even usable for smoothly coating the entire interior surface of a container such as a barrel.

By way of illustrating an extremely difficult application of the present invention, I am going to show particularly its utility in coating the interior of a beer barrel.

In the past beer barrels have generally been made of wood and coated with pitch or composition. More recently such barrels have been made of metal and the pitch or composition coating has been modified in order to render them adhesive to steel. The frequency with which such coatings require replacement has suggested that the interior of the steel barrel be provided with a metallic coating of such a nature as to resist corrosion and produce no deleterious effect upon the contents of the barrel. Aluminum suggests itself as a desirable material because it is cheap, sufliciently flexible to stand the knocks to which the barrel is subject, substantially noncorrosive, and not in any way harmful to beer. It was found, however, that the aluminum could not satisfactorily be deposited on the interior of the completed barrel by any known means. The

largest opening with which the barrel was provided was altogether too small for any electrode which would be sufiiciently large to make electroplating feasible. The most nearly acceptable known method involved the introduction of 5 molten aluminum into the barrel and the discharge therefrom of any surplus. It was found, however, that the thickness of the deposit on the metal could not be accurately gauged and the surface of the deposit was invariably rough 10 and tended to make the barrel unsanitary. While useful for many purposes, this method was not as desirable for this specific purpose as that herein disclosed.

By means of the invention hereinafter to be 15 disclosed, aluminum has been used successfully to line the interior of a steel barrel to produce a smooth and sanitary surface therein. Aluminum is chosen as the example because metallurgists regard the coating of aluminum on steel 20 as being one of the most diflicult metallurgical problems. The process and apparatus hereinafter to be disclosed are successfully usable for coating with aluminum and may also be used for any other metal, as for example, the surfac- 5 ing of ordinary steel with special steel such as cobalt or stainless steel.

The drawing shows apparatus of two different forms suitable for carrying out the present invention. a

Figure 1 is a plan view of apparatus usable for metallically coating the interior of a barrel.

Figure 2 is an enlarged detail view of the fragment of a barrel in section during the coating operation. 35

Like parts are identified by the same reference characters throughout the several views.

The apparatus shown in Fig. 1 is substantially a duplicate of that illustrated in my companion application No. 740,662 filed August 20, 1934. 40 In effect it is a centrifuge in which the barrel may be mounted for turning it upon its longitudinal and transverse axes, the whirling on at least one axis being accomplished not only at differing speeds, but also in reverse directions. 45

The shaft 5 provides a potential rotatable support for a yoke 6 having a headstock l and a' tailstock 8 detachably engageable with the barrel l0. When the supporting shaft 5 is rotated by means of belt ll the barrel is turned end for 50 end about a transverse axis. When yoke 8 is horizontal the barrel may be turned on its longitudinal axis and accelerated, decelerated or reversed by engaging the chuck I2 with the squared end of its headstock spindle I. 66

Mounted upon the base I! is a slide I! carrying a motor I! which drives the chuck I! through any suitable reversing gear mechanism.

In order to provide the barrel N with a metal- The powdered metal is preferably mixed with .15 a suitable flux. The flux may. however, be independently coated upon the interior of the barrel if desired. The advantage in mixing the flux with the powdered aluminum consists in the fact that an excess of flux may be used as a vehicle for assisting in the coating of the interior of the barrel with the aluminum. For example, the liquid flux and powdered aluminum may be introduced into the barrel in bulk through the bung hole and the barrel rotated on its support to distribute the aluminum over the interior, after which the surplus flux may be dumped out. The powdered metal may also be sprayed on to the surface to be coated, or in some applications of the invention, it may conveniently be brushed on. The manner of its distribution over the surface to be plated is broadly immaterial.

Having coated with flux and with powdered metal the surface to be plated, said surface is preferably (but not necessarily) heated. In

coating steel barrels with aluminum it has been found expedient to heat the barrel to a temperature between 600 degrees F. and 1290 degrees F. 1100 degrees is a very satisfactory temperature. With the barrel thus heated, a large quantity of balls of assorted sizes are introduced into the barrel through the bung hole, as best shown in Fig. 2 in which the balls 20 clearly appear. The number of such balls is broadly immaterial. They may be warm or cold. Ordinary highly polished steel ball bearings have been found to be very useful.

When the balls are in the barrel in sufficient quantities (for example) to fill the barrel from one sixth to one third full, the barrel is rotated on one or both of the axes on which it is mounted for rotation in such an apparatus as that shown in Fig. 1. If the balls achieve the speed of the barrel and rotate unitarily therewith, the rate of motion is either changed or the direction of rotation reversed so that the balls are preferably kept in a state of constant rotative movement respecting the barrel in which they are mounted. Due to the change in rate of movement the balls will tend to change their position in the barrel, and since they are of varying sizes they will roll all interior surfaces thereof. During the end over end rotation of the barrel, which preferably occurs first, the balls will usuallynotroll about the surface of the barrel but will be tumbled so as to strike all portions of the surface with a considerable impact.

I have found that both the impact and the rolling are effective to drive the powdered coating material (in this case the powdered aluminum) into the pores of the steel wall of the bar rel, with the result that a continuous and relatively non-porous metallic lining is "produced. Such a lining completely coats the interior of the barrel, closing andcovering all crevices or joints therein and providing a smooth, continuous, imperforate, one piece lining.

Either the rolling or the hammering alone may be used and, as above indicated, the heating of the barrel is not essential to the successful operation of the process, although it ,facilitates and expedites the production of a smooth lining.

Any suitable flux may be used according to the metals to be joined. The flux may either be applied preliminarily to the supporting metal, or it maybe mixed with the powdered metal which is to form the coating.

I claim:

1. The process of lining a metal barrel, which consists in the introduction through a small hole in the barrel of a pulverulent metallic lining material, a suitable flux and a plurality of balls, the heating of the barrel and the rotation thereof, whereby to distribute the lining material in the barrel and to roll it into a continuous coating for the interior thereof.

2. The process of coating a non-cylindrical metal barrel having a small aperture, which process includes the preparation of the interior surface of thebarrel to receive the coating, the introduction therein of a pulverulent lining material, and a series of balls in sufficient number to reach all portions of the inner surface of the barrel, the application of heat, and the rotation of the barrel, whereby to distribute the lining material and to roll it into intimately bonded relation to the entire inner surface of the barrel.

3. The process of coating the interior of an elongated metallic article which is not perfectly cylindrical on its inner surface, which process includes the preparation of the inner surface of said article to receive a bonded coating, the introduction into the article of a pulverulent metallic lining material, and a number of balls of differing sizes in suflicient quantities to reach all portions of the surface of the article during the rotation thereof, the application of heat, and the rotation of the article, whereby to displace said balls therein and thereby to distribute the lining material and to roll it into intimately bonded relation with the entire inner surface of the article.

FREDRICK GE'I'I'ELMAN. 

